1. Field of the Invention
The present invention relates generally to an ink ribbon which may be employed in a color printer so as to allow a user to know the color of an image before printing and/or an amount of ribbon which has been used.
2. Description of the Prior Art
Japanese Patent First Publication No. 62-297184 discloses an ink ribbon utilized for continuous color printing in a thermal color printer. The ink ribbon is permeated with three ink color blocks, such as yellow (Y), magenta (M), and cyan (C) (or four ink color blocks further including black (B)). The three ink color blocks overlap each other on one sheet of printing paper during printing operation so that a desired full color image may be printed.
Such an ink ribbon is usually accommodated in a ribbon cartridge for convenience. Single and double reel types of ribbon cartridge are well known in the art. The single reel type ribbon cartridge includes therein only one ribbon supply reel, a ribbon take-up reel is provided in a printer. The double reel type ribbon cartridge includes therein both ribbon supply and take-up reels winding a ribbon therebetween.
In operation, when the ribbon cartridge is loaded into a color video printer, it engages a ribbon feeding mechanism including capstan and pinch rollers so that the ink ribbon is extracted from the supply reel toward the take-up reel at a constant speed. During this operation, a platen lapped with a sheet of printing paper rotates repeatedly in normal and reverse directions so that the three colors are printed sequentially on the printing paper overlapping each other.
In a such conventional color printer, a ribbon cartridge which is coupled with a set number of sheets of a special printing paper is usually used. Thus, an amount of the unused ribbon may deduced by counting the number of unprinted sheets of paper. This is however quite inconvenient for a use and it is difficult to know an exact amount of unused ribbon accurately.
Further, there has been recently proposed a new type of thermal color printer which may utilize regular sheets of printing paper. Therefore, in such a color printer, since the ribbon cartridge need not be matched with sets of a particular type of paper, a user cannot determine an amount of unused ribbon by checking the remainder of printing paper and printing operation may become disrupted, further inconveniencing the user.